The invention relates to expandable structures, which, in use, are deployed in interior body regions of humans and other animals.
The deployment of expandable structures, generically called xe2x80x9cballoons,xe2x80x9d into cancellous bone is known. For example, U.S. Pat. Nos. 4,969,888 and 5,108,404 disclose apparatus and methods using expandable structures in cancellous bone for the fixation of fractures or other osteoporotic and non-osteoporotic conditions of human and animal bones.
When deployed in cancellous bone, expandable structures should undergo expansion and distention without failure. Furthermore, such structures, when distended, should generally match the geometry of the interior bone space in which the structure is deployed. In addition, such structures should permit compaction of areas of lowest bone density. Exposure to cancellous bone also typically requires materials having resistance to surface abrasion and/or tensile stresses.
It is has been determined that expandable structures incorporating elastomer materials, e.g., polyurethane, which have been preformed to a desired shape, e.g., by exposure to heat and pressure, can undergo controlled expansion and further distention in cancellous bone, without failure, while exhibiting resistance to surface abrasion and puncture when contacting cancellous bone.